Methods and devices for suture anchor delivery

ABSTRACT

A method for impacting a suture anchor into bone comprises providing an implantable suture anchor and providing an impactor device for impacting the suture anchor into the bone. The suture anchor is coupled to a distal portion of the impactor device. Positioning the suture anchor engages the anchor with the bone at an implantation site, and powering the impactor device impacts the suture anchor thereby implanting the suture anchor into the bone. The frequency of impaction is less than 20 KHz. The impactor device is then decoupled from the suture anchor, and the impactor device may be removed from the implantation site.

CROSS-REFERENCES TO RELATED APPLICATIONS

The present application is a divisional of U.S. patent application Ser.No. 13/692,596 filed Dec. 3, 2012 which is a continuation of U.S. patentapplication Ser. No. 12/605,065 filed Oct. 23, 2009 which is anon-provisional of and claims the benefit of U.S. Provisional PatentApplication No. 61/108,420 filed Oct. 24, 2008; the entire contents ofwhich are incorporated herein by reference.

BACKGROUND OF THE INVENTION 1. Field of the Invention

The present disclosure relates to medical devices, systems and methods,and more specifically to methods, systems and devices used for anchoringsuture and delivery of suture anchors.

Soft tissue such as tendons, ligaments and cartilage are generallyattached to bone by small collagenous fibers which are strong, but whichnevertheless still can tear due to wear or disease. Examples ofmusculoskeletal disease include a torn rotator cuff as well as a tornlabrum in the acetabular rim of a hip joint or the glenoid rim in ashoulder joint.

Thus, treatment of musculoskeletal disease may involve reattachment oftorn ligaments, tendons or other tissue to bone. This may require theplacement of suture anchors in the humeral head for reattachment of atorn rotator cuff, placement of suture anchors in the acetabular orglenoid rim for reattachment of the torn labrum, placement of tacks toattach labral tissue to the glenoid rim, placement of screws in thevertebral bodies to attach cervical plates for spinal fusion, placementof screws in small joint bones for stabilizing reduced fractures, etc. Asuture anchor is a device which allows a suture to be attached to tissuesuch as bone. Suture anchors may include screws or other tubularfasteners which are inserted into the bone and anchored in place. Afterinsertion of the anchor, the tissue to be repaired is captured by asuture, the suture is attached to the anchor (if not alreadypre-attached), tension is adjusted, and then the suture is often knottedso that the tissue is secured in a desired position.

Delivery of a suture anchor to a treatment site can be time consumingand challenging to undertake in the tight space encountered duringendoscopic surgery and sometimes even in conventional open surgery. Inmost surgical procedures, a pilot hole is drilled at the implantationsite prior to screwing in the device. In other cases a self-tappingdevice tip is used to screw in the device without a pilot hole.Alternatively, ultrasonic energy has been proposed in embedding boneanchors in bony tissue without pre-drilling a pilot hole. These methodsof implanting a device in bone tissue, while commonly used in surgerytoday, are not optimal. Pre-drilling a pilot hole prior to placing thedevice requires the surgeon to exchange tools through the cannula and tolocate the pilot hole after introducing the implant in the arthroscopicfield. Self-tapping devices are limited to use at sites with theappropriate thickness of cortical bone. Ultrasonic energy based devicesare susceptible to large energy losses with minor changes in deviceconfiguration, and rely on ultrasonic energy sources which can beexpensive. It would therefore be desirable to provide a suture anchorsystem that provides easy access to the treatment site and that caneasily and accurately deliver a suture anchor to a desired location.

In a particular application, treating musculoskeletal disease in a hipjoint can be especially challenging. The hip joint is a deep jointsurrounded by a blanket of ligaments and tendons that cover the joint,forming a sealed capsule. The capsule is very tight thereby making itdifficult to advance surgical instruments past the capsule into thejoint space. Also, because the hip joint is a deep joint, delivery ofsurgical instruments far into the joint space while still allowingcontrol of the working portions of the instrument from outside the bodycan be challenging. Additionally, the working space in the joint itselfis very small and thus there is little room for repairing the joint,such as when reattaching a torn labrum to the acetabular rim. Thus, thesuture anchor tool must be small enough to fit in the limited space.Moreover, when treating a torn labrum, the suture anchor must be smallenough to be inserted into the healthy rim of bone with adequatepurchase, and the anchor also must be short enough so that it does notprotrude through the bone into the articular surface of the joint (e.g.the acetabulum). Thus, the anchor delivery instrument must also be ableto hold and deliver suture anchors having a small diameter and smalllength.

Therefore, it would be desirable to provide improved suture anchors andsuture anchor delivery instruments that overcome some of theaforementioned challenges. Such suture anchors and delivery instrumentsare preferably suited to arthroscopic procedures, and in particularlabral repair in the hip. At least some of these objectives will be metby the disclosure described below.

2. Description of the Background Art

Patents disclosing suture anchoring devices and related technologiesinclude U.S. Pat. Nos. 7,566,339; 7,390,329; 7,309,337; 7,144,415;7,083,638; 6,986,781; 6,855,157; 6,770,076; 6,767,037; 6,656,183;6,652,561; 6,066,160; 6,045,574; 5,810,848; 5,728,136; 5,702,397;5,683,419; 5,647,874; 5,630,824; 5,601,557; 5,584,835; 5,569,306;5,520,700; 5,486,197; 5,464,427; 5,417,691; and 5,383,905. Patentpublications disclosing such devices include U.S. Patent PublicationNos. 2009/0069845; 2008/0188854; and 2008/0054814.

BRIEF SUMMARY OF THE INVENTION

The current invention comprises surgical devices and methods to treatvarious soft tissue and joint diseases, and more specifically relates tosuture anchors and suture anchor delivery instruments used in thetreatment of bone, cartilage, muscle, ligament, tendon and othermusculoskeletal structures.

In a first aspect of the present invention, a method for impacting asuture anchor into bone comprises providing an implantable sutureanchor, and providing an impactor device for impacting the suture anchorinto the bone. The suture anchor is coupled to a distal portion of theimpactor device. Positioning the suture anchor engages the suture anchorwith the bone at an implantation site, and powering the impactor deviceimpacts the suture anchor thereby implanting the suture anchor into thebone. The frequency of impaction is less than 20 KHz. The impactordevice is decoupled from the suture anchor and then the impactor deviceis removed from the implantation site.

The suture anchor may pass through adjacent musculoskeletal tissues andmay attach the adjacent musculoskeletal tissues to the bone. Theadjacent musculoskeletal tissues may comprise bony tissues or softtissues. The suture anchor may include one or more lengths of suture.Powering of the impactor device may comprise pneumatically,electrically, mechanically, or magnetically actuating the impactordevice. The impactor device may impact the anchor when powered so as tolinearly, rotationally, or linearly and rotationally drive the sutureanchor into the bone. The frequency of impaction may be less than 1 KHz.The impaction may have an amplitude of 1,000 micrometers or less perimpact.

The method may further comprise expanding a portion of the suture anchorradially outward so as to firmly engage the suture anchor with the bone.The suture anchor may comprise a plurality of fingers, and expanding aportion of the suture anchor may comprise releasing a constraint fromthe fingers so as to allow the fingers to radially expand outward. Theimpactor device may comprise an elongate tubular shaft and the step ofdecoupling may comprise advancing the suture anchor axially away from adistal portion of the shaft. The method may also comprise cooling thesuture anchor or the implantation site with a fluid.

In another aspect of the present invention, a suture anchor deliverysystem comprises an implantable suture anchor having a longitudinal axisand a plurality of fingers circumferentially disposed therearound. Thefingers have a constrained configuration and an unconstrainedconfiguration. In the constrained configuration the fingers aresubstantially parallel with the longitudinal axis, and in theunconstrained configuration, the fingers expand radially outward. Thesystem also includes an impactor device for impacting the suture anchorinto bone. The suture anchor is releasably coupled to a distal portionof the impactor device.

In a further aspect, the invention provides a suture anchor formed ofshape memory material and having an unbiased configuration adapted tosecurely fix the anchor in bone or other tissue. The suture anchor isdeformable into a configuration adapted for delivery into the bone ortissue, from which it may be released so that it returns toward itsunbiased configuration thereby anchoring the anchor in the bone ortissue. In various embodiments, the anchor may have in its unbiasedconfiguration a plurality of resilient fingers that extend radiallyoutward, a curved shape formed around a transverse axis, two or morewings that flare outwardly in the proximal direction, or two or morelongitudinal divisions defining a plurality of axial elements that bowor deflect outwardly. Other structures are disclosed herein.

In another aspect, the invention provides a suture anchor having atapered tip adapted for being driven into bone, with or without apre-drilled hole, a shaft extending proximally from the tip, and a meansfor attaching a suture to the shaft. The tip, the shaft, or both arecross-shaped in cross section.

The suture anchor may comprise a textured outer surface to allow forbone ingrowth. The suture anchor may also comprise a length of suturecoupled thereto. The impactor device may impact the suture anchor at afrequency of less than 20 KHz, or at a frequency of less than 1 KHz. theimpactor device may comprise an actuation mechanism for impacting thesuture anchor that is pneumatically, electrically, magnetically, ormechanically actuated. The impactor device may impact the suture anchorand drive the anchor into the bone or other tissue in a linear,rotational, or linear and rotational manner. The impactor device mayimpact the suture anchor with an impaction having an amplitude of 1,000micrometers or less per impact. The system may further comprise acooling system for cooling the impactor device and suture anchor duringimpaction. The cooling system may comprise a cooling fluid.

These and other embodiments are described in further detail in thefollowing description related to the appended drawing figures.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a sectional view of an anchor loaded in the distal end of ananchor driver and placed through a cannula.

FIG. 2 is a sectional view of a flat anchor loaded into the distal endof an anchor driver with a stabilization sleeve.

FIG. 3 is a sectional view of a round anchor loaded into the distal endof an anchor driver with a tubular profile.

FIG. 4 is a sectional view of the body of a pneumatic powered impactor.

FIG. 5 is a sectional view of the body of a electromechanically poweredimpactor.

FIG. 6 is a sectional view of the body of an impactor with a rotarymechanism.

FIG. 7 is an example of an anchor.

FIGS. 8A-8D are examples of anchors.

FIGS. 9A-9B are examples of anchor in a constrained and deployedconfiguration.

FIGS. 10A-10B are examples of a device for sutureless attachment oftissue to bone in a constrained and deployed configuration.

FIGS. 11A-11B are examples of a curved anchor in a constrained anddeployed configuration.

DETAILED DESCRIPTION OF THE INVENTION

The devices and methods disclosed herein address at least some of thelimitations of current methods of implanting devices into bony tissue.The method involves driving the device into bony tissue by impactionwhereby, an impactor drives the implant into bone at frequencies between10 and 20 KHz, preferably between 20 and 1000 Hz, most preferablybetween 30 and 500 Hz; and at amplitudes of 100 to 1000μ, preferably200-750μ, most preferably 300-500μ. The implantable device may be loadedinto the distal end of the impactor such that the distal end of theimpactor and the attached device may be introduced into an arthroscopicfield through a cannula.

FIG. 1, shows a sectional view of implant 103 loaded into an impactor102 and introduced through a cannula 103. Implant 101 is located at thedistal end of impactor assembly 102. The assembly 102 is introduced downthe bore of cannula 103 and placed in the proximity of bony structure104. Having been placed at the surface of bony structure 104 theimpactor 102 is energized and the implant 101 is driven into the bone.Channel 105 extends transversely through the implant 103 and allows asuture to be secured thereto. During the impaction period, contactbetween the tip of the device and the bony tissue is maintained manuallyby the surgeon.

In one exemplary embodiment the implant is impacted into the bone byapplication of force onto the proximal surface of the implant. Referringto FIG. 2, implant 201 is impacted by impactor member 202. This allowsthe implant 201 to be constructed with substantially consistent crosssections. Sleeve 203 can move relative to the implant 201 and impactormember 202 while remaining concentric and serves to stabilize and guidethe implant 201 while the implant 201 is being impacted into the bone.

In another embodiment the implant is configured with a stepped shoulderregion 303 along the length of the body suitable for applying impactionforce. FIG. 3 shows a cross sectional view of anchor 301 which has around cross section and interfaces with the distal end of the impactor302. The distal end of the impactor 302 is generally round and hollow.The distal end of the impactor 302 which interfaces with the anchordevice 301 could be of varying length to enable introduction throughcannulas used to access joint spaces in the shoulder, knee, hip etc. Theimpactor 302 may also be loaded with multiple devices.

At the frequencies utilized during deployment of anchors, the amount ofenergy loss by heat dissipation is low. However, the distal end of theimpactor may optionally be designed to circulate cold fluid to regulatethe temperature of the impactor tip and the implant. Other forms ofcooling well know in the art may also be used in conjunction with theimpactor.

The frequency and amplitude of the impactor may be adjusted to optimizethe implantation process depending on the size of the implant, thedesign of the implant, as well as the properties of bone at the implantsite, etc.

In another embodiment, the impactor is powered by compressed gas whichis commonly available in operating rooms. FIG. 4 shows a cutaway view ofone embodiment of a pneumatic driver used for placing devices in bonytissue. Shuttle element 401 is cycled back and forth based on airpressure by selectively pressurizing and releasing pressure in chamber402 through the cyclic motion of shuttle 401 relative to ports 403 and404. As the shuttle moves port 403 is selectively covered or uncoveredcausing the shuttle to reverse direction based on the action of spring405 which rebounds shuttle 401 back into the depressurized chamber 402.At one end of the shuttle travel, the shuttle impacts active element 406which is in contact with the proximal end of the device 407 therebytransmitting the energy from the shuttle 401 to the device 407 with eachcycle. At the end of the cycle, the spring 408 returns the activeelement 406 back to its original position. Those skilled in the art willappreciate that the system shown in FIG. 4 is an exemplary system andthe same effect could be accomplished with a variety of pressureddriving mechanisms.

In another embodiment, the impactor could be designed to operate using amechanical shuttle mechanism driven by an electromagnetic field. FIG. 5shows a sectional view of an instrument used for driving devices intobony tissue. Shuttle element 501 may be composed of any ferromagneticmaterial and is cycled back and forth based on the magnetic fieldcreated by a coil 502 which is connected to a signal generator capableof generating alternating current. At one end of the shuttle travel, theshuttle impacts active element 503 which is in contact with the proximalend of the device 504 thereby transmitting the energy from the shuttleto the device with each cycle. Those skilled in the art will appreciatethis system shown in FIG. 5 is an exemplary system and the same effectcould be accomplished with a variety of electromechanical drivingmechanisms.

In another embodiment, the impactor could be designed to operate usingmechanical means whereby rotary motion is converted to linear motion.FIG. 6 shows a sectional view of an instrument used for driving devicesinto bony tissue. Cable driven cam 601 is designed with a circular ramp602 that interfaces with mating ramp 603 that is part of shuttle 605that does not rotate due to pin 604 and slot in 603. Rotation of ramp602 causes mating ramp 603 to move in a reciprocating fashion which istransmitted to the active element 606 which in turn imparts its energyto implant 608. Shuttle 605 returns to its original position once ramps602 and 603 have disengaged via the force applied by spring 607. Thisallows active element 606 to return due to the force applied by spring608. Those skilled in the art will appreciate this system shown in FIG.6 is an exemplary system and the same effect could be accomplished witha variety of mechanisms that convert rotational motion intoreciprocating motion.

In all the embodiments described above, by altering the pressure,current, rotational speed etc., the frequency and amplitude of theimpactor can be varied to enable the surgeon to select settings that areappropriate for various tissue properties (e.g.; cortical bone,cancellous bone, etc.)

In addition to the embodiments described above, the impactor may havelinear and rotational motion combined to create a reciprocating twistingmotion. By creating a reciprocating twisting motion, devices may bedriven in more securely into bony tissue, thereby increasing thestability of the implanted device. The amount of twisting motion may bevaried based on the specific design and dimensions of the device. FIG. 7illustrates an exemplary embodiment of a suture anchor device 702 havinga pointed distal tip 706 and a main shaft 704. Both the main shaft 704and the distal tip 706 have a twisted, helical-like configuration sothat the anchor will rotate as it is being driven into the bone by animpactor having a reciprocating twisting motion.

The impaction method has advantages that are not limited to a particulardevice design. For example, the implant may be cylindrical, flat, or ahave a variety of other cross sections. Additionally the cross sectionmay change along the length of the implant. FIGS. 8A-8D show a varietyof anchor devices that may be useful in this application. The implantmay be threaded or plain. FIG. 8A shows an anchor with a tip 801 whichhas a triangular pointed tip while the shank 802 has a substantiallyround cross section. Shank 802 has a hole 803 that passes through theshank allowing for attachment of a suture. FIG. 8B shows an anchor 810having a rectangular cross section 812 resulting in a generally flatconfiguration. FIG. 8C shows an anchor 816 with a cross sectiongenerally described as a hollow tube and a suture S coupled thereto. Inthe embodiment shown in FIG. 8C, wings or fingers 804 and 805 are activeelements that deploy once the implant is released from the deliveryinstrument. For example wings or fingers 804, 805 may be fabricated froma superelastic material like Nitinol, spring temper stainless steel, aresilient polymer, or the wings may be fabricated from a shape memoryalloy, such that once the anchor 816 is advanced from the deliveryinstrument and the wings 804, 805 become unconstrained, they springopen, radially outward. The wings help secure the anchor 816 into boneor other tissue. In alternative embodiments, the wings 804, 805 may bedeformed into the flared radially outward position to help secure theanchor into the bone. For example, a plunger may be advanced into thecenter of the anchor thereby causing the wings 804, 805 to flareoutward. FIG. 8D shows an anchor 814 with a tip 814A and a shank 814Bhaving a generally X-shaped or cross-shaped cross section that mayinserted into bone using the techniques described herein. In theembodiment shown, both the tip and the shank of anchor 814 have across-shape cross-section, although in other embodiments just the tip orjust the shank may have a cross-shape. Shank 814B has a transverse holethrough which a suture may be threaded. Other means of attachment of thesuture to the shank may also be used.

Additionally, the implant and driver could be designed such that aloaded implant constrained by the driver is placed at the implantationsite. Following placement, the implant recovers to a pre-determinedshape that enhances the anchoring of the implant in the bony tissue.FIG. 9A shows a cylindrically shaped tubular expandable anchor 906 inits loaded (constrained) condition. The anchor comprises a plurality ofaxially oriented slits 905 that form a plurality of axially orientedelements 901. Element 901 is an active element that can be constrainedto the profile of the non active portion of the implant 902. Element 901is replicated in a circular pattern around the periphery of the implant906. Conically shaped nosecone 903 is distal to the end of the driverinstrument (not illustrated) while the shank is composed of activeelements and non active portions 901 and 902 respectively. The anchor906 is constrained in the delivery instrument. FIG. 9B shows the sameanchor 906 in its deployed configuration after being released andunconstrained from the delivery instrument (not illustrated). Elements901 are self-expanding and thus have moved to an expanded position tolock the anchor into the bony tissue. The elements 901 may be fabricatedfrom self-expanding materials such as superelastic nitinol, shape memoryalloys, spring temper metals, resilient polymers, or other resilientmaterials. Expansion element 901 causes a shortening of the overallanchor 906 length. In the case where there is a preloaded suture or softtissue fixation element attached to 901, this shortening of theanchoring element can be used as a tensioning means for the soft tissuefixation element. Tensioning the soft tissue fixation would provideimproved coaptation of the soft tissue to the bone, and improve therepair. The degree of foreshortening can be programmed into the deviceby modifying one or a combination of the diameter of the distal driving(pointed) element of 901, the length of the shaft of 901, the diameterof the shaft of 901, and the specific design of the cutouts 905 of 901.

Change in the implant after implantation could be based on the expansionof the body of the anchor as shown in FIG. 9B or by deployment of afixation member from the body of the anchor as shown in FIG. 8C. Acombination of the expansion of the body of the anchor and deployment ofmembers from the body could also be used. Expansion of the anchor couldinclude mechanical means of expanding the anchor from a firstconfiguration to a second configuration based on the malleability of thematerial or could be achieved through the use of self-expanding or shapememory materials. Deployment of fixation members may be achieved throughvarious means including shape memory and mechanical means. The implantsmay include one or more sutures. The body of the implant may have holesto allow for bony in-growth into or across the implant. The surface ofthe implant may be textured or porous to allow for bone in-growth toenhance long term anchoring of the implant. The implant may be hollow toallow for bony in-growth within the implant. An advantage of using ahollow implant is the entrapment of the bone particles from theimplantation site within the implant during impaction.

An additional embodiment of the current invention is an anchorconfigured to provide for fixation of tissue directly to the boneadjacent to the anchor location. FIG. 10A shows the anchor in aconstrained configuration for delivery. Active elements 1001 areconstrained in this undeployed state in the distal end of the driver(not illustrated) while nosecone 1002 may be exposed beyond the distalend of the driver. FIG. 10B shows the same anchor after it has beenplaced in bony tissue and the anchor has been deployed from the deliveryinstrument so that it is unconstrained. Active elements 1001 include aplurality of fingers that are axially aligned with the longitudinal axisof the anchor when constrained, and expand radially outward whenunconstrained. The elements spread out and allow for the capture oftissue between the fingers and the bone or other tissue into which theanchor is disposed. Nosecone 1002 is affixed into bony tissue. Byvarying different parameters of element 1001 which may include but arenot limited to the thickness, material, heat treating, and radius ofcurvature of the deployed device, it will be possible to change theforce of apposition between the two tissues to be fixed. This designalso provides a degree of self-adjustment, allowing different tissuethicknesses to be attached to underlying bone by a single device withoutrequiring a suture. By having a radius of curvature which changes alongthe length of the active elements 1001 rather than a constant radius ofcurvature, the device can be programmed to provide approximately thesame force of apposition for a range of tissue thicknesses to theunderlying bone with the same device design. This allows a surgeon touse a single cartridge-loaded device to place a number of anchorswithout device exchange.

Element 1001 may be made from a resorbable material such as PLLA,collagen, highly crosslinked hyaluronic acid or the like. While some ofthese materials may be processed and formed to self-deploy as describedabove, many require secondary steps after placement to deform them intoa fixation shape. As an example, when element 1001 is made from PLLA, asecondary step may include application of heat to element 1001 toplastically deform it into the desired final configuration. Once theheat source is removed, the PLLA or other plastically deformablematerial remains in its final shape and position. In other embodiments,the elements 1001 may be fabricated from self-expanding material likenitinol, spring temper metals, or resilient polymers. The elements mayalso be made from shape memory materials including metal alloys likenitinol or shape memory polymers.

Additionally, elements 1001 and 1002 may be two separate elements, withelement 1001 being placed on top of the tissue to be fixed, and 1002being driven down through element 1001 and into the underlying bone,fixing element 1001 and tissue to be fixed. In this embodiment, element1001 may be slotted as shown, or it may be configured more like a washeror grommet shape.

In another embodiment both the portion of the anchor located in bonytissue and the anchor portion in the adjacent tissue may be configuredwith both elements being active.

In yet another embodiment, an anchor 1102 may be constructed with agenerally curved profile as shown in FIG. 11A. FIG. 11B shows the anchor1102 once it is loaded into a delivery system 1103 which constrains itto a generally straight profile within a constraining sleeve 1101 thatis part of the driver. As the anchor 1102 is deployed from theconstraining sleeve 1101 into the bone, it advances along a curvedprofile into the implantation site.

The implants described in this invention could be made from metals likestainless steel, titanium, nitinol, etc., as well as resorbable andnon-resorbable polymers like PLLA, PEEK etc. Implants may also becomposites of two or more materials.

The method, devices and implants described above could be used in avariety of applications including any application that requires animplant to be anchored into bony tissue. For example, placement of boneanchors in the humeral head for reattachment of a torn rotator cuff,placement of bone anchors in the acetabular or glenoid rim forreattachment of the torn labrum, placement of tacks to attach labraltissue to the glenoid rim, placement of screws in the vertebral bodiesto attach cervical plates for spinal fusion, placement of screws insmall joint bones for stabilizing reduced fractures, for treating stressurinary incontinence with a bone-anchored pubovaginal sling, placementof plates in cranio-facial reconstruction, fixation of fractures, etc.

While the device and implants are designed to be used preferably inarthroscopic or minimally invasive procedures, they could also beutilized in open or mini-open surgical procedures.

The implants in this invention may be loaded into a delivery device(e.g. a tube) which can be attached to the distal end of the impactor.The loaded delivery device may be designed to be introduced through astandard arthroscopic cannula and may contain one or more implants,thereby enabling the implantation of multiple implants without removingthe delivery tool from the arthroscopic field. The delivery device mayhave features like a slit to enable manipulation of sutures attached tothe implant. Alternatively, the sutures may pass through the body of thedelivery device and be accessible through the proximal end of thecannula.

Example 1

An impactor device was fabricated similar to the device shown in FIG. 4.Air pressure was used to cycle a metal shuttle that impacts the activemember at the distal end of the impactor. A cylindrical anchor (proximaldiameter=1.5 mm, body diameter=2 mm) with a conical distal tip (lengthof anchor=6 mm), was loaded into the distal tip of the impactor. A #2braided polyester suture was attached to the anchor via a hole throughthe minor diameter of the anchor. The distal tip of the active memberhad an OD of 2 mm and ID of 1.5 mm, and a slit to allow for egress ofthe suture. The impactor anchor assembly was connected to 90 psicompressed air. The distal end of the assembly was placed in contactwith fresh cadaveric bovine cortical and cancellous bone. An air supplyvalve was opened and the anchors were driven into the bony tissue withease. The pullout strength of the anchors were assessed subjectively andindicated good fixation of the anchors. The anchors were then carved outof the bony tissue and the surrounding tissue was examined for grossdamage. There was no sign of thermal necrosis or other damage at theimplantation site.

While the above detailed description and figures are a completedescription of the preferred embodiments of the invention, variousalternatives, modifications, and equivalents may be used. The variousfeatures of the embodiments disclosed herein may be combined orsubstituted with one another. Therefore, the above description shouldnot be taken as limiting in scope of the invention which is defined bythe appended claims.

What is claimed is:
 1. A method for impacting a suture anchor into bone,said method comprising: providing an implantable suture anchor;providing an impactor device for impacting the suture anchor into thebone, the impactor device having a movable impactor element, wherein thesuture anchor is coupled to a distal portion of the impactor device;positioning the suture anchor into engagement with the bone at animplantation site; powering the impactor device to move the impactorelement relative to the suture anchor in a plurality of cycles such thatthe impactor element impacts the suture anchor during each cycle therebyimplanting the suture anchor into the bone; decoupling the impactordevice from the suture anchor; and removing the impactor device from theimplantation site.
 2. The method in claim 1, wherein the suture anchorpasses through adjacent musculoskeletal tissues.
 3. The method in claim2, wherein the suture anchor attaches the adjacent musculoskeletaltissues to the bone.
 4. The method in claim 3, wherein the adjacentmusculoskeletal tissues comprise bony tissue.
 5. The method in claim 3,wherein the adjacent musculoskeletal tissues comprise soft tissue. 6.The method in claim 1, wherein the suture anchor attaches soft tissue tothe bone.
 7. The method in claim 1, wherein the suture anchor comprisesone or more lengths of suture.
 8. The method in claim 1, wherein thepowering comprises pneumatically actuating the impactor device.
 9. Themethod in claim 1, wherein the powering comprises electrically actuatingthe impactor device.
 10. The method in claim 1, wherein the poweringcomprises magnetically actuating the impactor device.
 11. The method inclaim 1, wherein the powering comprises mechanically actuating theimpactor device.
 12. The method in claim 1, wherein the powering impactsthe anchor so as to linearly and rotatably drive the suture anchor intothe bone.
 13. The method in claim 1, wherein the frequency of impactionis less than 1 KHz.
 14. The method in claim 1, wherein the impaction hasan amplitude of 1000 micrometers or less per impact.
 15. The method inclaim 1, further comprising expanding a portion of the suture anchorradially outward so as to firmly engage the suture anchor with the bone.16. The method in claim 15, wherein the suture anchor comprises aplurality of fingers, and wherein the expanding comprises releasing aconstraint from the fingers so as to allow the fingers to radiallyexpand outward.
 17. The method in claim 1, wherein the impactorcomprises an elongate tubular shaft and the decoupling comprisesadvancing the suture anchor axially away from a distal portion thereof.18. The method in claim 1, further comprising cooling the suture anchoror the implantation site with a fluid.
 19. The method of claim 1,wherein the frequency of impaction is less than 20 KHz.
 20. The methodof claim 1, wherein the suture anchor comprises a plurality of fingers,the method further comprising constraining the plurality of fingers witha constraint so the plurality of fingers are axially aligned with alongitudinal axis of the suture anchor.
 21. The method of claim 20,further comprising releasing the constraint from the plurality offingers thereby allowing the plurality of fingers to expand radiallyoutward.
 22. The method of claim 21, further comprising capturing tissuebetween the plurality of fingers and the bone.
 23. The method of claim22, further comprising changing a force of apposition between thecaptured tissue and the bone.
 24. The method of claim 1, wherein themovable impactor element is disposed within a chamber of the impactordevice, and wherein powering the impactor device moves the impactorelement within the chamber relative to the suture anchor in a pluralityof cycles.
 25. A method for impacting a suture anchor into bone, saidmethod comprising: providing an implantable suture anchor having aplurality of fingers extending therefrom; providing an impactor devicefor impacting the suture anchor into the bone, wherein the suture anchoris coupled to a distal portion of the impactor device; positioning thesuture anchor into engagement with the bone at an implantation site;impacting the suture anchor into the bone; capturing tissue between theplurality of fingers and the bone; decoupling the impactor device fromthe suture anchor; and removing the impactor device from theimplantation site.
 26. The method of claim 25, wherein the suture anchorpasses through adjacent musculoskeletal tissues.
 27. The method in claim26, wherein the suture anchor attaches the adjacent musculoskeletaltissues to the bone.
 28. The method in claim 27, wherein the adjacentmusculoskeletal tissues comprise bony tissue.
 29. The method in claim27, wherein the adjacent musculoskeletal tissues comprise soft tissue.30. The method in claim 25, wherein the suture anchor attaches softtissue to the bone.
 31. The method of claim 25, further comprisingpowering the impactor device to impact the suture anchor into the bone.32. The method in claim 31, wherein the powering comprises one or moreof: pneumatically actuating the impactor device; electrically actuatingthe impactor device; magnetically actuating the impactor device; ormechanically actuating the impactor device.
 33. The method in claim 25,wherein impacting the suture anchor comprises linearly and rotatablydriving the suture anchor into the bone.
 34. The method of claim 25,wherein the impaction has a frequency less than 1 KHz.
 35. The method inclaim 25, wherein the impaction has an amplitude of 1000 micrometers orless per impact.
 36. The method in claim 25, wherein the impactorcomprises an elongate tubular shaft and the decoupling comprisesadvancing the suture anchor axially away from a distal portion thereof.37. The method in claim 25, further comprising cooling the suture anchoror the implantation site with a fluid.
 38. The method of claim 25,wherein the frequency of impaction is less than 20 KHz.
 39. The methodof claim 25, further comprising changing a force of apposition betweenthe captured tissue and the bone.